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arXiv 1507.04493astro-ph.CO
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LoCuSS:星系团的弱透镜质量校准

LoCuSS: Weak-lensing mass calibration of galaxy clusters

Nobuhiro Okabe, Graham P. Smith

摘要:

我们目前的弱透镜质量测量的50个X射线发光星系团在$0.15\le z\le0.3$,基于统一的高质量的观测与Suprime-Cam安装在8.2米斯巴鲁望远镜。我们密切关注可能的系统性偏倚,旨在将其控制在$\le4$ %水平。在弱透镜测量单个星系团质量时,系统偏差的主要来源是背景星系星表被微弱星系团和前景星系所污染。我们扩展我们的保守方法选择背景星系的$(V-i')$颜色红比红色序列的集群成员使用的颜色切割,取决于集群中心半径。这使我们能够定义背景星系样本遭受$\le1$百分之污染,并包括$13$星系每平方角分。由于我们的背景星系目录的纯度,最大的系统,我们在我们的分析中确定的是$3$ %的形状测量偏差,我们测量使用模拟探测弱剪切高达$g=0.3$。我们的个人集群质量和浓度测量与质量浓度关系的预测非常一致。同样,我们的叠加剪切剖面与Navarro Frenk和White剖面非常一致。我们新的LoCuSS质量测量结果与CCCP和CLASH调查一致,并与$\sim1-2σ$意义上的“称量巨人”相一致。总的来说,在$z\le0.3$的共识,是从这些互补的调查出现了重要的进展,集群质量校准,并预示着良好的集群宇宙学。

英文摘要:

We present weak-lensing mass measurements of 50 X-ray luminous galaxy clusters at $0.15\le z\le0.3$, based on uniform high quality observations with Suprime-Cam mounted on the 8.2-m Subaru telescope. We pay close attention to possible systematic biases, aiming to control them at the $\le4$ per cent level. The dominant source of systematic bias in weak-lensing measurements of the mass of individual galaxy clusters is contamination of background galaxy catalogues by faint cluster and foreground galaxies. We extend our conservative method for selecting background galaxies with $(V-i')$ colours redder than the red sequence of cluster members to use a colour-cut that depends on cluster-centric radius. This allows us to define background galaxy samples that suffer $\le1$ per cent contamination, and comprise $13$ galaxies per square arcminute. Thanks to the purity of our background galaxy catalogue, the largest systematic that we identify in our analysis is a shape measurement bias of $3$ per cent, that we measure using simulations that probe weak shears upto $g=0.3$. Our individual cluster mass and concentration measurements are in excellent agreement with predictions of the mass-concentration relation. Equally, our stacked shear profile is in excellent agreement with the Navarro Frenk and White profile. Our new LoCuSS mass measurements are consistent with the CCCP and CLASH surveys, and in tension with the Weighing the Giants at $\sim1-2σ$ significance. Overall, the consensus at $z\le0.3$ that is emerging from these complementary surveys represents important progress for cluster mass calibration, and augurs well for cluster cosmology.

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